The invention relates to a thermal cut-out or a heating system, particularly a glass ceramic cooking unit, with a substantially rod-shaped temperature sensor having an outer tube and an inner rod located therein having different expansion coefficients and which is provided for operating a signal switch arranged in a base and a circuit breaker also arranged in the base for switching off the heating means at a predetermined maximum temperature, a transfer member with actuating members connected to the base-side end of the inner rod acting on actuating points of both switches located roughly in the extension of the inner rod.
DE-OS No. 34 23 086 discloses a thermal cut-out of this type, in which the transfer member controlled by an inner rod constructed as a tension member, in the form of an actuating ram is passed through bores in the switch and is covered at both ends so as to be inaccessible from the outside. The actuating members are formed by the end face of a narrower ram part and the shoulder face of a larger diameter ram part, whose reciprocal spacing is fixed, so that no relative adjustment is possible through a direct spacing change between these two actuating members. Thus, for an adjustment of the signal switch independently of the adjustment of the circuit breaker, it is e.g. necessary to bend an end of a connecting lug carrying an opposite contact of said switch, which scarcely permits a precise adjustment. Admittedly other adjusting measures or means, such as adjustable screws, compression plates, etc. have been proposed for this purpose, but it is not possible as a result thereof to modify the relative spacing between the actuating members. DE-OS No. 33 33 645 discloses a thermal cut-out, in which one switch is operated by the inner bar via a reduction lever, but at the operating point at approximately 540.degree. C. this gives extremely small operating paths if the temperature amplitude is made correspondingly small, so that the precise temperature limitation can then be impaired. However, with this construction, it is possible to very precisely adjust the reciprocal spacing of the two actuating members.